The present invention relates in general, to flight controls for a projectile and, in particular to a new and useful control system for a preferably wingless guided piece of ammunition.
Such a guided ammunition usually comprises a more or less compact ammunition body without wings or fins, which moves in a ballistic flight while rotating about its longitudinal axis. To be able to guide such an ammunition during the flight toward a point to be hit, devices for varying the trajectory of the ammunition are needed.
German OS No. 28 15 087 discloses a projectile control particularly for artilliry or a rocket, for correcting the trajectory of the projectile by a controlled sideward discharge of gas jets. In addition to a power source delivering a gas stream to a plurality of discharge apertures arranged over the periphery of the projectile, a distributor is provided by which the gas stream is split and directed into enlarging conduits. The reaction control is effected either by enlarging or contracting the discharge apertures, or by varying the intensity of the discharged jets. The discharge apertures through which the gas jets are expelled are so arranged at the outer surface of the projectile that the resultant of the forces thereby produced passes through the center of gravity of the projectile.
Such a control system is expensive in manufacture, sensitive to disturbances, and suitable only for controlling rockets, at most.
Also known from German OS 07 57 664 is a device for varying the trajectory of a projectile, comprising a pulse jet rocket engine oriented in the axial direction of the projectile and equipped with at least one nozzle directed at an angle to the projectile axis, for producing pulses in a line passing through the center of gravity of the projectile. The nozzle ends of the combustion chambers of the jet engine are located at the point of the projectile. In this system which is suitable particularly for fin-stabilized projectiles, the trajectory is varied by controllably opening the nozzles and igniting the jet engine. This reaction control requires a pulse jet rocket engine occupying a large part of the available ammunition space.
Further, German AS No. 11 47 144 discloses a jet propulsion missile equipped with jet nozzles which are disposed in planes passing through the axis of the missile, at an angle to this axis. To pivot them and thus correct the trajectory, the nozzles or their parts are connected to a control mechanism. By increasing the angle of the nozzle jets at one side of the projectile axis and reducing it or keeping it unchanged at the other side, a torque is produced for changing the trajectory. The nozzle control mechanism is expensive and requires much space.